package com.admin.common.utils.security;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.security.MessageDigest;

/**
 * Md5加密方法
 *
 * @author fangchen
 */
public class Md5Utils {
    private static final Logger log = LoggerFactory.getLogger( Md5Utils.class );

    private static byte[] md5(String s) {
        MessageDigest algorithm;
        try {
            algorithm = MessageDigest.getInstance( "MD5" );
            algorithm.reset();
            algorithm.update( s.getBytes( "UTF-8" ) );
            byte[] messageDigest = algorithm.digest();
            return messageDigest;
        } catch (Exception e) {
            log.error( "MD5 Error...", e );
        }
        return null;
    }

    private static final String toHex(byte hash[]) {
        if (hash == null) {
            return null;
        }
        StringBuffer buf = new StringBuffer( hash.length * 2 );
        int i;

        for (i = 0; i < hash.length; i++) {
            if ((hash[i] & 0xff) < 0x10) {
                buf.append( "0" );
            }
            buf.append( Long.toString( hash[i] & 0xff, 16 ) );
        }
        return buf.toString();
    }

    public static String hash(String s) {
        try {
            return new String( toHex( md5( s ) ).getBytes( "UTF-8" ), "UTF-8" );
        } catch (Exception e) {
            log.error( "not supported charset...{}", e );
            return s;
        }
    }
}
